A one compartment dishwasher of the type used in large-scale kitchens and restaurants is in most cases a dishwasher with hood but may also be a front-loaded dishwasher. In the one compartment dishwasher, articles to be washed are placed in a rack which is placed in the dishwasher compartment of the dishwasher and is retained there during a dishwashing programme. During the dishwashing programme, the articles are first flushed with a dishwashing liquid and then with a rinsing liquid. The dishwashing liquid is circulated from the dishwashing container to the dishwashing compartment, over the articles and back to the dishwashing container. The dishwashing liquid is heated to about 60° C. and a dishwashing detergent is added. The rinsing liquid is completely pure liquid from the rinsing container, which liquid is heated to about 85° C. and a drying agent is added. After rinsing, the rinsing liquid flows down into the dishwashing container and dilutes the dishwashing liquid, which means that dishwashing detergent must be added to a corresponding degree after each dishwashing programme. In each rinsing, the rinsing liquid and the drying agent therein are thus consumed. In each rinsing, about 3-5 l of rinsing liquid is consumed. In view of the frequency of use for this type of dishwasher, it is important for both environmental and economical reasons to reduce, during each dishwashing programme, the consumption of energy, water and additives, however without increasing the volume of the dishwasher.